This is the published version of this article. Reproduced by permission of the publisher. Published version (c)Royal Netherlands Society for Agricultural Sciences, available from http://library.wur.nl/ojs/index.php/njas/article/viewArticle/478

Citation:

Otten, W., et al. 1999. Spatial and temporal dynamics of water in the root environment of potted plants on a flooded bench fertigation system. NJAS - Wageningen Journal of Life Sciences. 47(1): pp.51-65. Available from http://library.wur.nl/ojs/index.php/njas/article/viewArticle/478

Abstract:

The relationship between evapotranspiration of potted plants on a flooded bench fertigation
system and the realised distribution of water in the root zone was studied in detail for a range
of fertigation schedules. The physical characteristics of the peat-based potting medium are
described by models commonly used in soil physics. The functioning of the substrate in
practical situations was highly affected by hysteresis in the water retention characteristic.
Daily evapotranspiration of Ficus benjamina plants varied from 0.4 to 4.1 kg m-2 day-1, of
which 19-41% was lost by evaporation. Water uptake by plant roots resulted in near hydrostatic
equilibrium conditions as long as the volumetric water content was above 0.22. Lower
average water contents resulted in locally drier conditions in the root environment. The absorption
of water during irrigation depended on the soil physical conditions and increased
with decreasing volumetric water content before flooding. The majority of the water absorption
occurred within the first minutes, making frequent fertigation more effective than increasing
the duration. Actual buffer capacity of the potting medium is defined and by combining
measured absorption during flooding with data on evapotranspiration, we indicate
how minimum requirements of the fertigation schedule can be derived.